1. Field of the Invention
The present invention relates to methods that are useful for scanning and evaluating a continuous succession of bar code symbols. more particularly, the invention provides methods supporting the collecting and grouping of a plurality of scans for each respective bar code symbol in a succession of bar code symbols passing a scanner unit that is cycled on and off in a controlled manner.
2. Description of the Prior Art
A long standing need to verify and or evaluate the printed quality of bar code symbols is well known in the art. With the ubiquitous bar code symbol now used by virtually all inventory intensive establishments, such as warehouses and retail stores, methods to support the high speed evaluation and verification of bar code symbols, especially a succession of bar code symbols disposed on a moving substrate, are needed.
There are many hand held and fixed position bar code verifiers known in the art. Hand held systems enable a user to manually position a scanner unit to scan different portions of the symbol being verified. An analysis may then be conducted by the verifier to determine various evaluation parameters. These devices, and their methods of operation, are generally capable of evaluating and verifying individual bar code symbols in a manual manner. Hand held verifiers may be categorized into two fundamental groups of scanning verifies: contact verifiers and non-contact verifiers. Contact verifiers are physically placed in contact with the substrate on which the symbol is printed. Non-contact verifiers are generally scanner based apparatus, wherein the scanner is positioned at a fixed distance from the bar code symbol being evaluated. These systems are often manually operated to scan selected portions of a single symbol to be evaluated.
Some non-contact verifying systems known in the art are configured to be mounted on bar code printers. These systems evaluate the quality of a bar code symbol as it is printed in an on-demand and synchronous manner. If the quality of the just printed symbol is determined to be below a pre-selected level, the printer can be stopped. In these systems, a significant amount of communication and connection is provided between the printing mechanism and the verifier. The fact that the paper advance means and the print head of the printing mechanism are under the control of a computer means, which also controls the verifier mechanism, greatly simplifies the starting and stopping of the scanning and verifying of each newly printed symbol. That is, the communication and connection between the printer and the verifier determines when the evaluation is to start. Thus, the location of the symbol is well established with this method of verification. In contrast, on high speed flexographic printing presses and the like, which are generally mechanical rather than electronic in nature, the exact location of the bar code symbols to be evaluated is not readily known. Further, often the bar code symbol to be evaluated and verified is disposed around other printed information, possibly making evaluation more difficult.
There is currently a need to have high speed verifier arrangements (with associated methods of operation) for use in demanding applications wherein a succession of bar code symbols must be rapidly evaluated in an automated fashion. For example, skilled persons will appreciate the considerable difficulty of evaluating bar code symbols being rapidly printed on a printing press. Especially, where the apparatus does not advance the paper substrate in sync with the verifier activities (i.e., the printing and verification are asynchronous processes), and the evaluation must determine a count of the number of symbols printed, verify decode and a variety of other well known evaluation attributes for each symbol (by processing a `distinct group` of scans taken of the symbol). Also, a system must suitably deliver the evaluation information to an operator or a monitoring system. It should be understood that the terms `processing` and `process`, when referring to scans taken of a bar code symbol, are defined as determining if the bar code symbol is decodable and further may include determining one or more evaluation attributes.
There is also a current need to evaluate in an automated fashion a succession of bar code symbols disposed on repeating regions, or in repeating images, on a substrate. A particular need would be satisfied by an apparatus that could evaluate a succession bar code symbols in (near) real-time and provide an immediate indication of the quality of each symbol. Such evaluation allows for the immediate response should a problem be detected in the quality of the symbols being applied to a substrate (e.g., being printed on a printing press). At a point in time were the symbols being applied are found to be of low quality, the printing press may be stopped and the cause of the problem ascertained and corrected. The press may then be restarted with little loss of material and the virtual elimination of the need to reprint and replace poorly printed bar code symbols.
At present, there are a variety of well known guidelines and standards used to quantitatively evaluate the quality of bar code symbols. A quality evaluation guideline published in September 1994 by the Uniform Code Council (UCC), is titled "Quality Specification for the UPC Printed Symbol". This document, which is hereby incorporated by reference, presents an overall methodology for printing and verifying the common Universal Product Code, UPC, symbol. In particular, parts 2 and 3 of the UCC document provide definitions and related subject matter for a number of evaluation attributes. The evaluation attributes, which are also known as SRP parameters, and very generally as figures of merit, may be determined and combined to indicate the relative quality of the evaluated symbol. The term `relative quality` can be assumed to be the quality of a bar code symbol with respect the level of quality established by well known standards and guidelines known to skilled persons.
With the advent of rigorous and well defined quantitative measures to evaluate bar code symbols, there is a need for improved methods to support high speed automated evaluation and verification, particularly where real-time evaluation is desired. Current standard evaluation guidelines, such as the UCC quality specification, call for a plurality of scans spaced along the height of the symbol to be collected and evaluated. The results of the processing of the individual scans must then be combined to determine a measure of quality indicative of the overall quality of the symbol. Whereas, this requirement can be manually satisfied with hand-held verifiers as discussed above, and with on-demand printers which control and coordinate the printing, scanning, and processing of symbols to be evaluated, there is an unaddressed need for arrangements and methods to enable the collecting and grouping of scans that are associated with, and correspond to, each individual bar code symbol in a succession of spaced bar code symbols.
Objects and or advantages of the present invention are, therefore, to provide new and improved methods to support the scanning of a succession of bar code symbols, especially to collect and group a plurality of scans for each scanned symbol, having one or more of the following, capabilities, features, and/or characteristics:
automated high speed detecting and scanning of each of a succession of bar code symbols; PA1 enables the collecting and grouping a plurality of scans associated with each scanned symbol; PA1 asynchronous delimitation between individual bar code symbols (with no supporting and specific `detection means` or additional structure; PA1 scanning conducted in a controlled manner with the scanner unit suitably cycled on and off (i.e. energized and de-energized); PA1 useful to extend the life cycle of scanner units via operation in the controlled manner; PA1 enables the collecting and accurate grouping of scans associated with respective symbols (of the succession of symbols) being evaluated); PA1 rapid determination of the quality of each symbol in a succession of bar code symbols; and PA1 employable to determine and indicate trends of increasing or decreasing quality of bar code symbols.